Ping Gong of Jin commissioned the making of a zither. However, its strings were all of identical thickness, with no distinction between the larger and smaller ones.
Once completed, Ping Gong summoned Shi Kuang, the court musician, to tune the instrument. Shi Kuang labored for an entire day but could not produce a harmonious melody.
Ping Gong blamed Shi Kuang for his incompetence. Shi Kuang explained: "In a zither, the largest string is like the ruler of a state, and the smaller strings are like his ministers. Each has its distinct role. Only through mutual coordination can they produce proper temperament; only through orderly arrangement can they create harmonious and pleasant music. Now, there is no difference in size between the large and small strings. This destroys the inherent system and order they must possess. How can I possibly tune such an instrument?"